About the participants in SHHS1

[+] [deleted] +0 points · over 1 year ago
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[-] mrueschman +0 points · over 1 year ago

Fengzhen,

No, not all participants in SHHS have sleep-disordered breathing.

From the study documentation:

From these parent cohorts, a sample of participants who met the inclusion criteria (age 40 years or older; no history of treatment of sleep apnea; no tracheostomy; no current home oxygen therapy) was invited to participate in the baseline examination of the SHHS, which included an initial polysomnogram (SHHS-1).

The SHHS sleep study represented the first sleep study for most of the participants. Many participants did have sleep-disordered breathing based on the sleep study results, but this was not the case for all participants.

Thanks for the question and for using the site!

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[-] Fengzhen Hou +0 points · over 1 year ago

Dear mrueschman,

Thank you very much for your kind reply. Just as you mentioned, "Many participants did have sleep-disordered breathing based on the sleep study results, but this was not the case for all participants." , then another question is how can I get the information that which participants don't have sleep-disordered breathing and other cardiovascular diseases? In my project, I need some "health controls" .

Thanks again and looking for your help.

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[-] mrueschman +0 points · over 1 year ago

To get some "health controls", I think your first step would be to pick and choose the variables you want to filter upon from our datasets. For instance, you mentioned:

  1. sleep-disorderd breathing, and
  2. cardiovascular diseases

For #1, a common variable to assess sleep apnea is the Apnea-Hypopnea Index, and one commonly used variable is AHI_A0H3. Typically AHI is categorized as follows:

  1. <5 = No sleep apnea
  2. 5-15 = Mild sleep apnea
  3. 15-30 = Moderate sleep apnea
  4. >30 = Severe sleep apnea

You could start with one of those cutoffs.

For #2, you might choose some of the prevalent condition variables in the Medical History folder. These variables indicate whether the participant had a diagnosis of things like heart attack or stroke at the time of the visit. Typically the responses are "0 = No" and "1 = Yes" for having the disease or not.

Good luck!

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[-] Fengzhen Hou +0 points · over 1 year ago

Dear mrueschman,

Thank you very much. I have got the needed information.

Would you please tell me what is the process to download the Heart rate (PR) records from SHHS?

Thank you for your precious time and kind reply again.

Fengzhen Hou

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[-] mrueschman +0 points · over 1 year ago

We do not have any processed heart rate (e.g. HRV) data posted for SHHS. These would have to be derived from the ECG channels in the EDF versions of the overnight sleep studies. I'm not that familiar with this type of data/analysis myself, so I probably can't provide much more help in this area. If you have more questions I can consult with some of my colleagues who are more familiar with heart rate analysis.

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[-] Fengzhen Hou +0 points · over 1 year ago

Thanks you very much, mrueschman.
Is there any HRV-extract tool available posted for SHHS?

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[-] mrueschman +0 points · over 1 year ago

Fengzhen: Nothing like that has been posted on NSRR for SHHS. For another study (CHAT), we have posted some results after a team member used the PhysioNET HRV Toolkit. You might find some helpful links from that tool's page.

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[-] Fengzhen Hou +0 points · over 1 year ago

Ok, mrueschman, i have got it. You are very kind and I'm grateful for your help to my work. Best wishes to you.

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[-] Fengzhen Hou +0 points · over 1 year ago

Excuse me, mrueschman. Could you please tell me what's the abbreviation “MD” in the sentence "MD said participant had heart failure?" standing for? The sentence "MD said participant had heart failure?" appears in the website of https://sleepdata.org/datasets/shhs/variables/hf15. I have try my best to find out that, however I failed. Thank you!

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[-] mrueschman +0 points · over 1 year ago

In this case, it means "Medical Doctor" (Doctor of Medicine). The participants were asked at the visit if a doctor or health professional had ever diagnosed them [the patient] with certain diseases / health conditions.

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[-] Fengzhen Hou +0 points · over 1 year ago

Thank you :)

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[-] Fengzhen Hou +0 points · over 1 year ago

Dear mrueschman, In the discription of SHHS dataset, I found that : The recording montage consisted of: C3/A2 and C4/A1 EEGs, sampled at 125 Hz right and left electrooculograms (EOGs), sampled at 50 Hz a bipolar submental electromyogram (EMG), sampled at 125 Hz thoracic and abdominal excursions (THOR and ABDO), recorded by inductive plethysmography bands and sampled at 10 Hz “airflow” detected by a nasal-oral thermocouple (Protec, Woodinville, WA), sampled at 10 Hz finger-tip pulse oximetry (Nonin, Minneapolis, MN) sampled at 1 Hz ECG from a bipolar lead, sampled at 125 Hz for most SHHS-1 studies and 250 Hz for SHHS-2 studies Heart rate (PR) derived from the ECG and sampled at 1 Hz body position (using a mercury gauge sensor) ambient light (on/off, by a light sensor secured to the recording garment)

So my first question is: Does there contain Heart rate signals in the EDF files?

In fact, I have had a try to read the edf files in matlab. No matter what kinds of signals, there are many extreme values (value >1000) appears regularly (one in 635 data points). I don't know why. Maybe there is a mistake in the reading code, but unfortunately, I haven't found it. Could you kindly do me a favor? I suppose the following sentence have a mistake: data = fread(fp,'int16');

There comes my second question : Is the signal data in edf files stored in "int16" type?

Thank you very much for precious time. Looking forward for your kind reply.

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[-] mrueschman +0 points · over 1 year ago

Fengzhen,

I am not that familiar with the EDF and the sleep recordings myself, but I am going to ask a couple other Core Members to review your question and comment if they have thoughts.

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[-] SaraMariani +0 points · over 1 year ago

Hi Fengzhen,

to answer your first question, yes, the EDF files contain a heart rate signal, that is named HR in SHHS1 and PR is SHHS2, is interpolated and sampled at 1 Hz and is in beats per minute (bpm).

To answer your second question, I believe there could be a mistake in the code you are using to open the EDF files, because I do not see these extreme values. The data are stored in double, not int16 format. I suggest you give our tool for reading EDF files a try: https://sleepdata.org/tools/block-edf-loader, it is very quick and easy to use.

Let us know how it goes!

Sara

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[-] Fengzhen Hou +0 points · over 1 year ago

Great thanks for Sara Mariani and mrueschman. I'll have a try.

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